I am new to the Glock 20 and it came with a Lone Wolf stock length barrel as well as the factory barrel. I will be reloading for it using mainly starline brass with various power loads.

I understand that because the chamber dimensions are supposedly tighter in the Lone Wolf the brass should last longer in it than the factory barrel or should I not even worry about it.

I'm also wondering what signs should I be looking for showing that the brass is about to give out with standard SAAMI pressure loads. I know about running the stuff past max data and how you can get into trouble like with anything else pushed too far. Or should I not worry about this with standard pressure loads?

Also whenever I get into something new with reloading I tend to be overly cautious. For example even though I have been reloading for over 10 years I held off loading shot sells for years because it seemed too complicated.

This is my first "high power" auto loader and I hear tons of horror stories and not a whole lot to make me feel comfortable. It seems like every ones answer to reloading 10mm is "you'll blow your head off"

So maybe I'm being overly cautious. You tell me.

What else do you reload ? If your Tag Name is accurate and you have reloaded for a M1 Garand for ten years....you will probably be fine.

Follow reputable reloading data and understand that faster isn't always better.

The 10mm is just like every other pistol round.

The Lone Wolf barrel offers better case head support than the factory Glock barrel... it might have a tighter chamber.. ( still within SAMMI specs though )

Frankly, your brass will probably ( at factory pressures ) split at the case mouth prior to any other problems.

Yes it is accurate. I started shooting the M1 and reloading for that matter when I was back in Highschool and was shooting high power matches with the same. That was probably back in 2002 or 2003.

Its hard to get an accurate measure of anything on forums because people like to speculate and exaggerate.

As it turned out shot shell loading is actually even more forgiving than loading metallic cartridges.

For me high pressure auto loader cartridges are a new thing. I have been loading 357 mag for years and 44 mag starting this past winter but nothing in this power range for auto loaders until now.  Before too long hopefully I will have a 460 Rowland conversion for this Glock as well. That should be fun.

If no one had ever mentioned a thing about unsupported chambers in Glock 20's "causing problems" I probably would have just gone on my merry way reloading with out giving it a second thought.

The concern is usually chamber support. Here is a pic from the web

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Less support in the 6 o'clock position is a result of the basic Browning design for an autoloader.  All modern semi-auto pistols has less support there.

Further, Glock has 'tightened up' their original chamber and feed ramp design over time.  The ones produced since the late 2000s are now similar to all other brands.   My 2005 G23 has the tighter chamber shown below.  Also, the two Glock barrels below have a slight beveled chamber mouth which gives them the appearance of having a huge chamber (while they don't).  It's there to ensure consistent feeding even when dirty.  Remember, the Glock was designed for the Austrian Army as a military combat weapon and reliable feeding, even if dropped in the mud, is a design requirement.

 
 
 
 
 
 

You will need to get Hornadys reloading manual. They are the only one that has full power loads. 155 gr doing 1450 fps. Blue dot is a very popular powder for the 10mm. And Hornady makes good bullets, also Hornadys book has a specific section for the M1.

I've been reloading the 10mm off and on for the past 20+ years. Case life has been as good as any other cartridge. I've loaded for stock Glocks, one with a Barsto and a Smith 1006, right now I'm loading for two Dan Wesson 1911's a 4.25" and 5"

For full power loads I like Accurate Arms data from their 5.0 pdf file, which you get download from their website. After one full power application I've been loading mild 165 gr. and 180 gr. FMJ's with a low dose of Win 231, these loads are running about 1000 fps and 975 fps respectively and the wife and I can shoot these all day which works for me. AA9 and AA7 are giving me excellent full power loads with 155, 165, 180 and 200 gain Gold dots and XTP's when I can find them. I don't load my 10 guns to "nuclear" levels, I've never seen the need. Book loads with AA data and powder has been sufficient.

My woods load is a Beartooth Bullet 200 gr. WFNGC with 8.2 grains of 800x, this gives me 1130 fps from my 4.25" Commander, I believe book max for a 200 gr. FMJ with 800x is 7.8 grains or so. I've been following the Glock Talk 10 ring guys for years and this would be considered a very, very mild load by comparison from what they do with 800x. Doesn't mean it's safe, just an FYI for reference. Personally I think some of the guys over there and on the newer 10mm website are pretty good handloaders, and then some are not. When I get around to it I intend to work up this load with AA9, 800x is just a PIA and each load MUST be hand weighed, the flakes are huge and don't meter well at all. Not to mention one needs to go off the books to get decent velocity which I'd rather not do. A caution on the BTB as well, it is an extremely wide bullet and requires extra attention to detail when loading, my 1911 chambers are tight, the above load at 1.250" has proven ok in both my pistols, new starline and cci-300s. But they will only feed in Tripp's Magazines.

Hornady 10mm loading info, I would use extreme caution, some of their loads are "snappy" as a lab rep at Accurate Arms recently described them to me, personally I would never, ever load as high as some Hornady data suggests, that goes for 9mm and AA loads too. My experience with Hornady info is from their 4th and 7th edition. I love Hornady products, but suspect some of their published load data. Which of course is why we always cross reference.

In my opinion the 10mm is a hand loaders dream, and the least appreciated auto loader cartridge out there, you can run 135 gr. to 220 grains, from 850 to over 1600 fps. If I had any one recommendation it would be to stock up on 500-1000 pieces of new Starline brass colored brass when you can get your hands on it. One other thing, initially I had some issues with an RCBS sizer die, not correctly sizing my 40 and 10mm brass, it drove my nuts for awhile, I've switched to Lee dies and the issue was resolved, I suspect the RCBS sizer is incorrectly sized, one of these days I'll mail it off for a new one.

With new full power loads I always load some dummies and test, and retest for any potential setback, correct neck tension is your friend and best found out with a dummy round Some of the factory brass I've collected over the years is thinner than others.

Any load data I've provided is from and old mans memory and I'm on my first cup of coffee as I quickly type this, ALL DATA IS SUSPECT AND ONLY WORKS IN MY GUNS. Do your own due diligence.

Good luck and enjoy!

"In my opinion the 10mm is a hand loaders dream, and the least appreciated auto loader cartridge out there, you can run 135 gr. to 220 grains, from 850 to over 1600 fps. If I had any one recommendation it would be to stock up on 500-1000 pieces of new Starline brass colored brass when you can get your hands on it. One other thing, initially I had some issues with an RCBS sizer die, not correctly sizing my 40 and 10mm brass, it drove my nuts for awhile, I've switched to Lee dies and the issue was resolved, I suspect the RCBS sizer is incorrectly sized, one of these days I'll mail it off for a new one. "

I've found the same to be true. 10mm is my favorite to reload and Blue Dot is my powder of choice. I recently loaded 1k of Hornady 180g HP-XTP with new Starline brass and Blue Dot. My Glock and my AR loves em.

I've found that the RCBS sizer die doesn't do a great job with 1x fired cases with the Glock bulge. The Lee resizer does.

Thanks for the great info.

10mm AR do tell

This is my experience.  

I'd regard visible case bulging as being a sign of a defective barrel.  Between a 2008-ish G20 and a 2012-ish Dan Wesson Razorback shooting "warm" loads, I've never had it happen.

10mm is awesome but there isn't any particular voodoo to loading it.  Matter of fact, it's the cartridge I learned on and it's always behaved perfectly,  

Just remember that, in the real world, the only thing that last 80fps of velocity you managed to eke out of a load is achieving is wearing the internals of your pistol faster and burning more powder.

I am also going to add a PSA.... with most all of these higher power auto-loaders, they use much stronger than usual recoil springs.

During assembly and dis-assembly that recoil spring can and will "launch" with a good deal of force... Be sure to wear safety glasses everytime !


I have always wanted a 10mm handgun and AR.

I also agree that the cartridge is vastly underrated.

It can be loaded from mild to wild. With a large bullet weight range .... what is not to like ?